Electron microscope study of the body wall and the gut of adult Loa loa.

The morphology of the body wall and the gut in the midbody region of adult male and female Loa loa originating from patients in Gabon was studied by transmission and scanning electron microscopy. The cuticle of the dorsal and ventral regions consists of ten layers. In the lateral regions the cuticle is thicker and includes two additional layers. The thin hypodermis contains numerous transhypodermal fibres. A row of median cells is situated between the syncytia in each lateral chord. No intracellular bacteria were observed. The cross-sections of each of the four muscle sectors are comprised of approximately 12 muscle cells of the coelomyarian type. The plasm of the gut cells contains large vacuoles and several mitochondria. The intestinal wall surrounds a wide lumen filled with material which occasionally contains cellular structures. The morphology of L. loa is compared with that of adult Onchocerca volvulus and Brugia malayi. The gut of the adult L. loa has the typical nematode morphology, which might be an indication of its normal function in nutrition. The multilayered cuticle with the rather smooth surface, and the prominent muscles correspond to the migratory activity of this filaria.